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By A. W. de Villiers

This paper explores the behaviour of methane in the goaf during longwall mining, together with some methods for the control of methane emissions into the goaf, the working face, and the ventilation system. Experimental work done at Twistdraai Colliery, Sasol Coal, is referred to, as well as the gas-drainage system being practised at West Cliff Colliery in New South Wales, Australia. Gas drainage is discussed briefly, and certain suggestions are made in regard to coal mining in South Africa.

Jan 1, 1989

By J. Nell

Heavy mineral deposits often contain relatively high levels of radioactive elements (thorium and uranium in particular).It is difficult to obtain clean separation of ilmenite and monazite (the main impurity mineral containing radioactive elements), and physical intergrowths of the two minerals are, in fact, not uncommon. As a result, ilmenite concentrates obtained from such deposits often contain high levels of thorium and uranium. Because of the large negative free energies of formation of ThO2and U3O8boththorium and uranium report to the slag during smelting and if an ilmenite concentrate contaminated with monazite is used to make high titania slag, the concentrations of these elements in the slag end up about 40% higher than in the ilmenite feed. Previous work, patented by RGC Mineral Sands Limited, and subsequently confirmed by Mintek, showed that radioactivity may be reduced by roasting an ilmenite concentrate with borax at 1000°C to 1100°C and leaching it with hydrochloric acid1. It is evident that the cost of an ilmenite roast/leach process will be high and there may be economic benefits in removing the radioactive elements from the slag instead (the volume of slag to be treated is smaller than the volume of ilmenite feed). To remove radioactive elements from the slag it is necessary to know how these elements occur in the slag. Inother words, the distribution of uranium and thorium between the various oxide, silicate and metallic phases in high titania slag must be determined. Once the deportment of thorium and uranium between the various phases ha sbeen determined, an appropriate process for slag purification can be developed. Test samples High-titania slag was prepared in a pilot-scale DC furnace from ilmenite concentrates with different levels of uranium and thorium. Subsequently, ten slag samples representing a range of compositions were selected for bulk chemical analysis, scanning electron microscopy and micro-analysis. The samples were crushed to a maximum particle size of 1 mm and from each sample a 20-kg batch was riffled out for analysis. Bulk chemical composition Chemical compositions of the samples selected for test work are given in Table I. TiO2, Al2O3, SiO2, MgO, MnO, FeO and V2O5were analysed by ICP-OES, Na2O, CaO andCr2O3by atomic absorption spectroscopy and U and Th by XRF (the XRF detection limit for U and Th was around 4 ppm). The ?B? series has a higher silica content than the others as a result of small silica additions that were made during smelting. All samples have elevated alumina levels as a result of furnace refractory contamination during smelting. As expected, there is an inverse relationship between the concentrations of TiO2and FeO in the samples (Figure 1).The TiO2and FeO levels are similar to the levels found in industrial slags2. Extreme conditions of reduction under which reduction of more ?refractory? oxides (e.g., chromia, magnesia, silica, alumina and even urania and thoria) might take place were not explored in the study. Note that BB1and BBB1 contain more than 7% combined silica and alumina (SiO2as a flux addition during smelting, and Al2O3from refractory contamination) and they do not fall on the general trend defined by the other samples. The U and Th concentrations of sample E2 is noteworthy. In the preparation of slag E2, monazite concentrate was added to the ilmenite to increase the concentrations of radioactive elements in the slag. This was done primarily to facilitate the detection of Th and U during the phase chemical characterization of the slag. Radioactivity measurements Gamma ray emissions from the samples were measured [ ]

Jan 1, 2007

The following contributions were received to the paper entitled 'Safety in South African mines: An analysis of accident statistics', by H.S. Eisner and J.P. Leger, which appeared in the J. S. Afr. Inst. Min. Metal., vol. 88, no. 1, Jan. 1988, pp. 1-7. Contribution by H. WAGNER* The paper by Dr H.S. Eisner and Mr J.P. Leger is critical of the safety situation on South African mines and portrays the industry as having little concern for the health and safety of its workers. Moreover, the casual reader gains the impression of deliberate misinformation by the industry to the public concerning safety maters. Furthermore, certain socio-economic reasons are advanced for the apparent differences between the fatality and injury rates reported for coal mines in South Africa and those for the United Kingdom. Contribution by S.A. WATTS. Authors Eisner and Leger are to be commended on their paper, which highlights, according to their interpretation, various shortcomings of both the Chamber of Mines accident statistics and those published by the Department of Mineral and Energy Affairs. Authors' Reply We gratefully acknowledge Dr Wagner's contribution to the discussion on our paper. For convenience, we shal use his sequence of comments in our reply. Before doing so, however, it may be useful to explain how our paper came to be written. After the explosion at Hlobane Colliery in 1983, one of us (HSE), in February 1984, was retained by the lawyers acting for some of the dependants of the victims to advise on technical maters relating to the explosion. Contribution by Ms S.A. Wats Some of the points made by Ms Wats have already been answered in our comments on Dr Wagner's contribution. We are fully aware that the number of accidents leading to absences of less than 4 days would be much greater than shown in our bar chart, and are grateful to Ms Wats for drawing attention to the specific exceptions that can make a 1-3 day accident compensable and that are clearly responsible for the relatively low count in that category of the chart.

Jan 1, 1988

By C. O. Beale

This, the second and final part of a review on the subject(the first part was published in the March issue of this Jouma/), deals in detail with the 9 copper-producing companies in the Republic of South Africa. These are The Phosphate Development Corporation, Prieska Copper Mines (Pty) Ltd, Black Mountain Mineral Development Co. (Pty) Ltd, Rustenburg Platinum Holdings Ltd, Impala Platinum Holdings Ltd, Western Platinum Ltd, The O'okiep Copper Co. Ltd, Messina Ltd, and Palabora Mining Co. Ltd. The following are described for each company: background, development, geology, mining, concentration, and current situation. The last-mentioned company, being South Africa's largest producer, is dealt with in greatest detail.

Jan 1, 1985

By A. J. Dickson, A. M. Starfield

This paper reviews the progress made to date in the development of computer models of heat and moisture transfer from rock surfaces to the ventilating air in deep-level mines. The application of these programs to ventilation planning and design is discussed.

Jan 1, 2014

By J. van der Walt, A. Whillier

Gravity-fed water systems in mines by A. WHILLlER, Pr. Eng., Se. D. (M.I.T.) (Fellow) and J. VAN DER WALT, Pr. Eng., B.A. Hons. (Bus. Admin.), Ph.D. (Eng.) (Visitor) South African mines often experience significant losses in production because of recurring shortages of water at work places as the result of underground dams running dry. Similar shortages have occurred during fire-fighting operations, and now, with the use of cold service water to aid in the cooling of mines, it is even more necessary that such shortages should be prevented. This paper draws attention to the primary cause of such water shortages, and an outline is given of some of the fundamental hydraulic principles that must be followed in the design of gravity-fed water-supply systems on mines.

Jan 4, 1977

R. C. J. Goode (President): South Africa is known for its sunshine and mineral deposits-especially its gold and its diamonds-and as this year marks the 75th Anniversary of the establishment of the South African Institute of Mining and Metallurgy, it is appropriate that I say a few words about mining and metallurgy and the part this industry and our Institute has played in the life of this country. Africa, as the Dark Continent, with its fascinating tales of Prester John, Ophir, Queen of Sheba and its myths and legends has throughout the ages fired the public imagination. Pharaoh Necho, 600 years before the birth of Christ, sent an expedition from Egypt around the Cape to probe this strange land. The gold for King Solomon's throne was said to come from Monomotapa-the country now known as Rhodesia. Centuries later the Arabs and Portuguese searched for this mineral wealth. The Arabs found little gold but unfortunately established a lucrative trade in black slaves. Now let us take a brief look into the closing stages of the Stone Age when the indigenous population of the lower portion of this continent consisted of the Bushmen, a nomadic hunting people who knew no metals and kept no stock, and the Hottentots who were a pastoral folk with cattle and sheep. Then somewhere about the 11th century the Bantu started their long migration southwards and brought with them the knowledge of smelting of iron ore. One of their settlements was here in Johannesburg on the Melville Kopje at Emmarentia. These people were the first miners and metallurgists on the Witwatersrand and the beautifully preserved iron smelting furnace constructed nearly 1,000 years ago is a tribute to their technical ability. This ability to use iron to make better spears for hunting or to fashion hoes for cultivating the soil led to their establishment as a superior tribe. The earlier Bushmen were pushed back to the inhospitable swamps and deserts and the Hottentots fled to the south. The Bantu also knew the art of copper smelting. In the days of the Dutch East India Company, at the end of the seventeenth century, Bantu workers brought copper from the north-west Cape to Simon van der Stel, but it was another two hundred years before the white man turned this to advantage. Stories of the Bantu mining gold spurred the early European hunters to travel deeper into the heart of Africa in search of wealth, and we are told that Karel Kruger, in 1834 whilst leading an ivory hunting expedition, discovered gold on the Witwatersrand, and took samples to Cape Town; but when he returned with a larger expedition a few years later his party was attacked by Moselekatze's Matabele near Potchefstroom. Kruger was killed and only the legend survived. The real spur to mining in this country was the discovery of diamonds in Griqualand West in 1867. The field seemed fabulously rich and diggers flocked to the scene from the four corners of the earth. With them came Cecil Rhodes, Barnato, Beit and some of the finest mining and financial brains the country had yet seen. These giant entrepreneurs were not tempted by the small deposits of gold in the Barberton and Pilgrim's Rest areas when these were made a few years later but

By H. M. Friede

Mining was a widespread economic activity in the African Iron Age. This paper reviews the available evidence on, the archaeological, historical, ethnological, and technological aspects of early mining in the Transvaal. A number of analyses of ores found at archaeological sites (especially at Broederstroom) are reported, and an interpretation of the analytical results is suggested. Descriptions of Iron Age copper- and tin-mining complexes, and of iron-ore workings, are given, and techniques of Iron Age mining are discussed. The evidence of gold mining in Iron Age Transvaal is examined.

Jan 1, 1980

The Western Cape Branch of the SAIMM recently held a one-day colloquium on the use of artificial intelligence (AI) in process engineering in the I.S. Gericke conference room at the University of Stellenbosch

Jan 1, 1992

By R. J. Kendall

As we enter the new millennium, the South African mining industry has to ensure that it becomes more competitive if it is to survive in the ever more demanding global environment. Traditionally, mechanization in narrow stopes has been limited to the use of scraper winches, and numerous mechanization attempts have been restricted to pilot projects operated on an extremely limited scale (with varying degrees of success). The benefits of hydropower are well documented, and Northam Platinum has shown these benefits to be achievable on a mine-wide basis. However, the equipment originally developed for hydropower systems has followed the traditional labour-intensive approach commonly used in deep level narrow stoping operations. The problems experienced with the hydropower system are discussed and the rationale for developing alternate technologies is explored. The hydropower system has shown to be a versatile powering medium which can be harnessed for a diversity of uses. It (hydropower) enables the mining engineer to change traditional paradigms and to design an entirely new approach for optimizing the mining operation based on explosive techniques. The system developed for Northam consists of the following: ?Purpose-built stope drill rig operated off the hydropower system with special features to ensure accurate drilling patterns throughout the length of the blast hole ?Purpose-built high rate cleaning system for rapid transfer of fractured ore to the stope orepass ?Redesigned stope layout to facilitate in-stope water control and to recover fines from the run-off water ?Purpose-built drill rig for rapid establishment of reef raises and advanced strike gullies ?Purpose-built drill rig for flat end development. On both types of development end rig, emphasis is placed on ensuring accurate drilling patterns throughout the length of the hole to maximize linear advance per blast. The paper discusses the implementation of the Northam system on a large scale as well as current initiatives to further improve on the efficiencies of mining operations. It concludes by emphasizing that mechanized hydropowered stope technologies are in their infancy and thus offer unlimited scope in progressing beyond today?s paradigms to present as yet unthought of solutions for optimizing deep level ore extraction.

Jan 1, 2000

By I. Bock

This presentation describes a technique under development referred to as Selective Blast Mining. The technique involves millisecond sequential blasting. It applies to mines where the gold bearing conglomerate band is clearly demarcated, and separated from the waste rock in the foot and hanging wall. The width of the conglomerate band should be less than ± 0,7 metres. A research program was initiated in August 1994 by Drs RE. Robinson and I.E. Bock. The objectives were to develop new blasting methods that can reduce: ? the losses of gold in narrow reef stoping. Losses of gold can be as much as 10-15% ? and to introduce selective mining to reduce ore dilution with waste rock.

Jan 1, 1996

By G. Poropat, A. R. Guest, H. P. Grobler

At the De Beers Consolidates Mines operations it is common practices to perform Geotechnical mapping of the newly exposed faces in the waste and ore rock. The purpose of Geotechnical mapping is to quantify the in-situ fracturing of a rockmass that in turn is required during the planning and application of a mining method. Whether it is to determine slope angles, caveability, impact of blasting or support requirements. This mapping involved a cumbersome and time consuming procedure that requires individual examination and description of the natural inherent fractures exposed by mining. During highwall mapping in an open pit this can be a safety concern due to the duration of time spent below a highwall. The advantages gained through the recent introduction and application of SiroVision® allows safer mapping, an increase in statistical fracture population, archiving of rock faces and the more accurate reflection of the true mapping. This paper aims to describe in detail the application of the recently developed SiroVision®, photogrammetry software, to replace conventional face mapping. A De Beers Consolidated Mines, il est pratique courante de faire une cartographie géotechnique des tailles récemment exposées dans le rocher stérile ou minerai. Le but de la cartographie géotechnique est de quantifier la fracturation in-situ d’une masse rocheuse, qui sera nécessaire lors de la planification et application d’une méthode minière, que ce soit pour déterminer les angles des galeries inclinées, les possibilités de foudroyage, l’impact du dynamitage, ou les besoins en supports. Cette cartographie nécessitait une procédure longue et compliquée qui demande l’examen individuel et la description des fractures naturelles propres exposées par l’opération de mine. Pendant la cartographie de parois dans une exploitation à ciel ouvert, cette opération peut être dangereuse à cause du temps passé sous la paroi. Récemment, le lancement et application de Siro Vision apportent l’avantage d’une cartographie plus sûre, une augmentation des statistiques de population de fracture, l’archivage des tailles de roches, et le reflet plus précis de la cartographie. Le but de l’étude présente est de décrire en détail l’application du développement récent de Siro Vision, logiciel de photogrammétrie, pour remplacer la cartographie de taille conventionnelle. Bei den De Beers Consolidates Mines Operationen ist es gängige Praxis geotechnische Aufzeichungen des Taub- und Erzgesteins neu geöffneter Abbaustellen zu erstellen. Zweck dieser geotechnischen Aufzeichnungen ist die vor-Ort-Quantifizierung des Bruches der Gesteinsmasse, welche im Gegenzug während der Planung und der Anwendung einer Abbaumethode erforderlich ist, sei es um einen Neigungswinkel festzustellen, Abbaubarkeit, Auswirkung von Sprengungen oder Anforderungen an Unterstützungen. Die Aufzeichnungen waren mit umständlichen und zeitaufwendigen Prozeduren verbunden, die eine individuelle Prüfung und Beschreibung der durch den Abbau freigelegten natürlichen inhärenten Brüche, verlangten. Dies kann auf Grund des Zeitraumes der unterhalb einer Flözoberschicht verbringt wird zu einer Frage der Sicherheit werden wenn die Aufzeichnung einer Flözoberschicht im Tagbau erfolgt. Die Vorteile auf Grund der jüngst erfolgten Einführung und Anwendung der SiroVision® gestatten sichereres Aufzeichen, eine Zunahme in der statistischen Menge an Gesteinsbrüchen und eine akkuratere Reflektion der tatsächlichen Aufzeichnungen. Diese Arbeit hat zum Ziel im Detail die Anwendung der kürzlich entwickelten SiroVision®, eine photogrammetrische Software, die die konventionelle Abbauortaufzeichnung ersetzen soll zu beschreiben.

Jan 1, 2003

By G. Vouille, P. Bérest

Residual stresses observed in rocks often result from non-compatible initial strains. These stresses can be determined when the incompatibility tensor associated with the initial strain tensor is known. The residual stresses in a cylindrical rock sample can be computed the sample is considered small enough for its incompatibility tensor to be constant. Les contraintes résiduelles, dont on observe couramment les manifestations dans les roches, résultent souvent de l’existence de déformations initiales non-compatibles. Ces contraintes peuvent être calculées lorsque le tenseur d’incompatibilité associé aux déformations initiales est connu. Les contraintes résiduelles dans une éprouvette cylindrique sont données dans le cas où le tenseur d’incompatibilité est constant. Eigenspannungen, die man haeufig in Steinen beobachtet, sind oft Ergebnis einer inkompatiblen Deformation des Anfangszustandes. Diese Spannungen koennen berechnet werden, wenn der Inkompatibilitaets-Tensor der Anfangsdeformation bekannt ist. Die Eigenspannungen einer zylindrischen Probe werden fuer Fall eines konstanten Inkompatibilitaets-Tensor bestimmt.

Jan 1, 2003

By P. R. Jochhens

The Past. In the past, large metallurgical companies (for example the mining houses) had the necessary infrastructure both to develop metallurgical flowsheets and to undertake the construction and project management of metallurgical plants. Effectively, the sole contribution by contracting companies was the supply, and possibly the installation, of specific items of equipment. OBITUARY: AUSTIN WHILLIER (1927 - 1981) On Thursday, 13th August, 1981, Dr. Austin Whillier passed away peacefully in Johannesburg after a long illness. This event has been a serious blow indeed, and its effects will be felt, not only by the Chamber of Mines of South Africa and the South African mining industry, but also throughout many scientific and technical spheres both in South Africa and further a field.

Jan 1, 1981

By N. C. Joughin, H. Wagner

Research is a business activity, and is as different from other business activities as banking is from mining. attempting to use research to solve their problems, managers do not always recognize its unique features, are frequently disillusioned with the outcome. With a view to enabling managers to use research more effectively, an outline is given of the features of research as applied to mining. Types of research are distinguished, and stages in the research-and-development process are identified. The time-scales and resource requirements of the various types and phases of research are explained. Examples of research that have reached implementation in gold mining are given to illustrate the features mentioned. Practical and economic considerations are discussed, and pitfals and recommendations in the use of research are highlighted.

Jan 1, 1989

The International Colloquium on Developments in Froth Flotation, which replaced the Annual University of Cape Town (UCT)/University of Stelenbosch (US) Minerals Processing Symposium, was held at the Van Riebeeck Hotel in Gordon's Bay on 3rd and 4th August, 1989. The Colloquium attracted 150 delegates from the mining, metallurgical, and chemical industries, including 9 from overseas.

Jan 1, 1989

By K. H. Berget, V. Andersen, H. Tveit, R. Jensen

This paper presents some of the work carried out in order to improve the tapping process in silicon production, with special focus on the environmental and the safety standards. Some of the modelling work that has been done to improve the understanding of the process is described, together with the resulting implementation to improve tapping standards.

Jan 1, 2014

Outotec?s direct leaching process is an atmospheric leaching process for sulphidic zinc concentrates. The direct leaching process, based on special leaching reactors developed by Outokumpu, is the most economical way to produce electrolytic zinc. The production scale applications of the process realized so far are in use at Boliden?s Kokkola and Odda zinc plants. A new full-scale application of Outotec?s direct leaching process will be started in 2008 in China. The process is integrated to the existing production plant, replacing part of the old production facilities by modern technology. Besides high zinc extraction the plant expansion and modernization offers also indium recovery, iron precipitation and solution purification processes. The process equipment includes tailor-made reactors designed on the basis of the work and experience of Outotec research center. Keywords: zinc, concentrate, atmospheric leaching, technology, indium, iron precipitation, solution purification, Outotec

Jan 1, 2008

By Nicolle Krusberski

Potential errors in XRF analysis are discussed and investigated with specific reference to the analysis of ilmenite samples. A selection of ilmenite samples was chosen and prepared using two XRF preparation techniques: pressed powder pellet and unroasted fusion bead. The merits of the two methods have been discussed in this paper for ilmenite analysis by XRF. Recommendations have been made regarding the use of pressed powder pellets especially with regard to the mineralogical effects that were evidenced during this investigation. The fusion bead technique was found to be far more accurate and able to meet short turnaround requirements provided the calibration methodology used is specific to the grade of samples analyzed.

Jan 1, 2014

By M. Tangstad, B. Monsen, H. Midtgaard

The increased attention towards reducing emissions of fossil CO2 due to its potential global warming effect has resulted in a focus on renewable resources, as charcoal. Since charcoal is produced from growing wood it does not contribute to global warming. This paper gives a brief review of consequences of and reasons for using charcoal in the silicomanganese (SiMn) production. Results are presented from practical SiMn smelting experiments, on a pilot scale, using charcoal as reduction material and comparing with coke. As slag- and CO2-reactivity are important for furnace performance these features have also been measured.

Jan 1, 2004